Two-cycle engine load control



J n.19,1937. 4105s- 2,067,954

I TWCPCYCLE ENGINE LOAD CONTROL Filed Aug. 19, 1932 gwoe'ntot v %0/7I7720ff Elm Patented Jan. 19, 1937 UNITED 'srATss "PATENT caries 9 Claims. (or. 123-103).

i This invention relates to internal combustion engines of the two-cycle type and has particular reference to a device for fully closing the throttle at high engine speeds and leaving the throttle to idle position at low speeds.

Experiments conducted with two cycle engines installed on automotive vehicles have proved that very objectionable intermittent firing takes place when the engine is to be slowed down and/or the vehicle brought to a stopfrom higher speeds, such as thirty miles per hour and over. The release of the accelerator pedal allows the throttle to move toward closed position but ordinarily leaves the throttle sufl'iciently .open--i. e. in idling position--which will cause the engine to fire after, three or four revolutions. This objectionable firing will v not take place when slowing down the engine if the throttle is fully closed to prevent carburetted air from reaching the firing chamber. -If a devicewere arranged so that at high engine speeds the throttle couldbe fully closed when the engine is being slowed down, better firing results, but this device should be so installed that for low speeds and idlingit will allow the throttle to assume the customary idle position. The device of the invention has for its purpose to accomplish the above-mentioned, object and consists in providing in the connection which leads from the throttle to the accelerator pedal, or other. member tooperate the throttle, a bellows which is subject, to the pressure in the fuel intake con-v duit on the outlet side of the usual blower. At high speeds this pressure will be appreciable and will be transmitted to the bellows to expandit. This expansion, when the accelerator pedal is released, will tightly close the throttle to its fullest extent in the intake riser. At low speeds the pressure of the blower is-very much diminished and this pressure will be insufilcient to afiect the bellows so that for slow speeds the throttle will be held slightly open or at idle position.

The single figure on the drawing is a sectional view through one cylinder of a multi-cylinder' two-cycle internal combustion engine with the invention applied.

Referring to the drawing, the numeral 2 indicates as a whole any two-cycle multi-cylinder internal combustion engine. The engine has the usual cylinders 4 having theexhaust ports 8 and the intake ports 8. The crankcase is indicated at III, the pistons at l2 and the connecting rods at l4. The piston is connected to the usual crankshaft, the axis of which is indicated at l8. At the top of thecylinder, there is applied any suitable combustion head N which, for purposes of disclosure only, is of the'special type shown. The combustion chamber for each cylinder includes the neck portion connected at one. end to the inlet 8 and at its other end having formed therein the rounded combustion chamber .22. This combustion chamber has the usual spark plug 24 at the top thereof. Connected to the combustion chamber 22 is the pipe 26 which also forms a part of the combustion chamber head I8. The-pipe 26 has a usual spark plug 28 which preferably is positioned immediately beyond the rotary valve 30 which controls the admission of carburetted air connected bymeans of the gears 40. A pipe 42 is connected to the outlet 44 of the blower and extends upwardly and is connected as at 48 to the inlet to the combustion chamber 26 at the rotary valve 38. The pipe 42 also includes the lateral by-pass extension 48 in which there is positioned the valve 58 urged toward closed position by the coil spring 52 as shown in the figure. The piston valve 50 has connected thereto the stem 54 which passes through a spacer 58 in the by-pas's conduit -48, and a second piston 58 is connected to the end of the stem 54 at the other side of the spacer 56. The piston 58 operates in the end of the by pass extension 48 and has a small air flow opening 59 therein. The piston 58 forms a dashpot. The spacer 56 is rigidly secured in place by one or more screws 88. j A suitable end closure 82 is provided for the end of the by-pass conduit 48.

The. usual carburetor is shown at 84, the riser therefrom at 66 which delivers at 68 to the blow er 34. A pipe 10 is connected to the by-pass connectlon 48 by the inlet 83.

The throttle valve'is shown at I2 mounted on a' shaft 14 having alever 16 secured thereto. The

' lever 16 is connected to a rod 18 which has a bellows 88 attached thereto. A rod'82 attached to the other endof the bellows-is connected with the usual accelerator pedal: 81. Inside the bellows 80 the rods" and82 may be telescopically arranged to form a more rigid structure. A fiexible'connection such as a hose 84 is connected to one end of the bellows while the other end is connected .to the extension .48 as,

opening in the end of a bracket 92 mounted on any suitable stationary part of the vehicle. The

end of the bracket is positioned between the stops 88 and 88.

Considering the position of the parts as shown in the figure, the pressure on the accelerator pedal and rod 82 has been ,released. the throttle I2 is in fully closed position and the bellows 88 expanded. Thisis the condition of a. relatively high pressure in the passages 42 and 48, or a pressure indicative of .high. speeds such as miles per hour or higher. In this expanded position, the bellows 88 will push the rod 18 to the right tightly to close the throttle 12 as indicated. The expansion of the bellows 88 will push the rod T8 to the right instead of pushing the rod 82 to the left because of the greater resistance oifered by the accelerator pedal which now is in released position and which has associated therewith the usual spring to hold it in a position corresponding to throttle closed position. speedsthe pressure in the passages 42, 48 will be considerably less so that the pressure trans- ,mitted through the connection 84 and bellows 88 will be insufficient to overcome the resistance or tension of the bellows to cause its expansion.

The bellows 88 will therefore be contracted from the position shown in the figure. the rod 18 and lever 16 a little to the left to open the throttle 64 slightly or to move it to a position to allow eificient idling.

When the throttle valve 12 closes it causes an increase in pressure in the conduits 42, 48 which pressure increase pushes the piston valve 58 to the left to open the inlet 83 of the pipe 18. This allows a lay-passing of fuel mixture through the blower 84.

1. In combination with an internal combustion engine having an induction system including a blower, a by-pass-to enable the carbureted fuel to circulate through the blower when excessive pressures are reached, and a throttle, means manually to operate thethrottle, a bellows to operate the throttle, said bellows. having its in terior connected at the by-pass to the air from the blower whereby to cause a full closing of the throttle at certain intake pressures and manual control settings.

2. In combination with an internal combustion engine having an induction system including a blower, a by-pass to enable the carbureted fuel to' circulate through the blower when excessive pressures are reached, and a throttle, means manually to operate the throttle, a second means to operate the throttle, said second means having its interior connected at theby-pass to the air from the-blower whereby to cause a full clos- 'ing of the throttle at certain intake pressures and manual control settings.

3. In combination with an internal combustion engine having an induction system including a blower, a by-pass to'e'nable the carbureted fuel to circulate through the blower when excessive For lower This will pull aoeaeea.

pressures are reached, and a throttle, means control settings.

4. In combination with an internal combustion engine having an induction system including a blower, a by-pass to enable the carbureted fuel to circulate through the blower when excessive pressures are reached, and a throttle, means manually to operate the throttle, means outside the induction system to operate the throttle, said second named means having its interior connected at the by-pass with the air from'the blower whereby to cause a full closing of the throttle at certain intake pressures and manual control settings.

5. In a two-cycle internal combustion engine, a blower to force carbureted fuel to the combustion chamber of the engine, a throttle valve be tween the blower and the combustion chamber, manual means to operate said throttle, and means having its interior subjected to the. airpressure of the blower and interrelatedwith said firstnamed means to close said throttle fully at certain intake pressures and manual control settings.

6. In a two-cycle internal combustion engine, a blower to force carbureted fuel to the combustion chamber of the engine, a throttle valve between theblower and the combustion chamber, manual means to operate said throttle, and a bellows having its interior subjected to the air. pressure of the blower and interrelated with said means to close said throttle fully at certain intake pressures and manual control settings,

7. In a two-cycle internal combustion engine, a blower to force carbureted fuel to the combustion chamber of the engine, a throttle valve between the blower and the combustion chamber, manual means to operate said throttle, and means having its interior subjected to the air pressure of the blower and interrelated with said firstnamed means to close said throttle fully at high intake pressure. and certain manual control settings.

8. In a two-cycle internal combustion engine, a blower to force carbureted fuel to the combustion chamber of the engine, a throttle valve between the blower and the combustion chamber, manual means to operate said throttle, and means having its interior subjected to the air pressure of the blower and interrelated with said firstof the blower and interrelated with said flrst-,

named means to close said throttle fully at high intake pressure and certain manual control settings at low speeds said throttle being capable of taking its idling position without interference from the pressure controlled means.

i JOI-IN ROSS. 

